常温低湿储藏对烤烟种子活力和萌发特性的影响

Variation on seed vigor and germination of tobacco stored at room temperature and low humidity situation

利用发芽试验、胚根表观性状扫描、电导率和抗氧化酶活性的测定,在常温低湿黑暗条件下,对种子活力和抗氧化能力进行研究。结果表明:新采收、储藏2.5年和储藏4.5年的种子发芽势和发芽率均无显著差异(P>0.05);储藏2.5年的种子水溶液电导率和抗氧化酶活性与新采收种子无显著差异,而储藏4.5年的种子电导率显著升高,抗氧化酶活性显著降低(P<0.05);储藏2.5年的种子胚根长度、胚根表面积和胚根体积显著大于新采收和储藏4.5年的种子或无显著差异(P>0.05)。可见在室温下,通过控制种子入库含水量和种子库相对湿度,使种子含水量保持在自由水临界点以下,种子活力和抗氧化能力的变化是一个缓慢的过程。种子活力变化初期,表现为胚根生长潜力的下降,幼苗表型也将变弱,同时种子发生膜脂过氧化;但胚根生长能力的丧失还需要一个较长的阶段,所以在种子活力变化初期发芽势(率)并不会明显下降。

Germination,radicle phenotype indexes,electrical conductivity and antioxidant enzymes were used to study the change of seed vigor and antioxidant abilities stored in dark,room temperature and low humidity seed bank.The results showed that there were no significantly differences on the germination potential and germination percentage among seeds stored for 0,2.5 and 4.5 years.The electrical conductivity and antioxidant enzymes had no significant difference between seeds stored for 0 and 2.5 years (P＞ 0.05),however,conductivity increased significantly and antioxidant enzyme activity descended significantly in seeds stored for 4.5 years (P＜0.05).Radicle length,surface area and volume of seeds stored for 2.5 years were significantly more than that of fresh seeds and seeds stored for 4.5 years or have no difference at all (P＞0.05).So,degradation of seed vigor and antioxidant capacity would be a slow process when the relative humidity of seed bank and the initial seed water content were appropriately adjusted at room temperature under which the free-water content of those seeds just below the threshold.Initially,radicle growth potential of the seeds reduced significantly and germination phenotypes were generally weak.In the meantime,seeds membrane lipid was also experienced of peroxidation.However,since losing of radicle growth potential was a long process,energy for germination and percentage of seeds would not reduce immediately at the early germination stage.